Goated primary-cell electrode



Patented Feb. 2681 924.

,umrsoisrnrss ensure-Fr es.

GEORGE W. HEISE, OF ELMHURST, NEW YORK, AND CLARENCE W. BROKATE, 0F DAN- IBURY, OHIO, ASSIGNORS TO UNION CARBIDE 6c CARBON RESEARCH LABORATORIES,

INC., A CORPORATION 01' NEW YORK.

doa'rnn PRIMARY-CELL nnnc'monn.

No Drawing. Application filed February T 0 all whom. it may concern.

Be it known that we, Gnoaon \V. HEISE and CLARENCE W'. Bnonn'rn, citizens of the United States, residing at Elmhurst and Danbury, respectively. in the counties of Queens and Ottawa and States of New York and Ohio, have invented certain new and useful Improvements in Coated Primary- Cell Electrodes, of which the following is a specification.

This invention relates to electric cells, and particularly to improvements in protective anode coatings adapted to inhibit giemical or electrolytic action on the anode uring the period in which the cells are on open circuit.

Deterioration of the anode always tends to occur, as it is impossible in commercial practice to insure the absence of conditions inducing local action, deposition of insoluble compounds on the surface of the metalsor other deleterious effects. The corrosion and incrustation of the anode is particularly harmful in cells which are used in open circuit work, such as dry cells. It is"'well known that these cells are subject'to damage or destruction, before service or during periods'of non-use, by reaction of the electrolyte with the zinc. Our invention, is primarily designed to inhibit undesired reactions in cells of this type, though it is not limited thereto.

W'itlra view to avoiding the above-mentioned disadvantages, it has been proposed to coat the inner surface of zinc container electrodes with paraflin or oils. If paraflin is used, it is necessary to melt it in order to expose the metal surface to electrolytic action. This is inconvenient, and the coating is effective only during the preservice life of the cell. Oils are only a partial protection, and give risethemselves to certain corrosion effects. Also, they tend to separate from the metal, making it neces sary to provide means, suchas a paper linin ',to retain them in position.

"e have discovered that improved results may be obtained by the application of a soap to the surface of the soluble electrode; in case dry cells of usual construction are in question, the soap is ap lied.to the inner surface of the zinc cup.. l ve prefer to use a soap which is substantially insoluble in the electrolyte solution. such as zinc oleate or 2, 1922 Serial 1V0. 533,551.

aluminum oleate. W'e ma however, use soaps comprising the high ritty acids other than oleic and a water-soluble soap may be employed in cases in which the electrolyte contains a heavy metal ion, as reaction takes place between the soap and the metal to form an insoluble layer on the electrode surface. Ordinar soft or hard soaps may be. used, prefers ly in alkaline solution. The caustic alkali extract of sawdust, espe cially ,ine sawdust, or resin soap in prepared hrm, is a. cheap and convenient material for coating the zinc.

The method of applying the soap is im material. By way of example, it may be said that when soaps insoluble in. water are used, it is convenient to dissolve them in a volatile solvent, such as benzene, and to brush or spray the solution on the metal. The soap lpay also he precipitated upon the zinc or applied in any other suitable Way, as, for instance, by mixing with aste and spreading the mixture in a thin ayer on the electrode. Heat may be applied to dry the soap and secure a firmly adherent coating.

Cells provided with a coating of the kind described are effectively protected against corrosion on open circuit, and therefore have a prolonged shelf life. The soap coating on the anode, being substantially insoluble, has no chemical effect on the cell, nor does it add materially to the internal resistance. The voltage and amperage of freshly prepared cells provided with the coating is not appreciably less than that of freshly prepared cells without it. Owing to the diminution of corrosion, the former cells give effective service for a considerably longer period than the latter.

The protective coating described herein may be. used with particular advantage in hermetically sealed dry cells, in which it is necessary to reduce so far as possible the generation of gases by corrosion of the zinc and other causes. The coating may, for example, he applied to the zinc electrodes of hermetically sealed cells of the type described and claimed in a plications Serial No. 481,715 and 481,716, fied by George W. Heise on June 80, 1921. The invention is in no Way limited to this use, however, but is of broad application as indicated by the scope of the appended claims.

2. An e ectrodo provided with a coating 5 comprising an aluminum soap.

3. In an electric cell, lneanii'for prevenfing corrosion of the anode while the cell, is on open .circmt, comprising a coating, containmg a soap, upon the anode.

10 4. In a dry cell, a zinc container-electrode,

and a coating, comprising a. soap, upon the interior surface of the zinc container.

$3. In a dry cell, a zinc container elccl rodc, and a coating of aluminum olcatc upon tho inner surface of the container.

In iostimony whereof, we affix our signalures.

GEORGE W. IIEISE. CLARENCE Vi. BROKATE. 

